/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package javax.servlet.jsp.el;

/**
 * <p>
 * This class is used to customize the way an ExpressionEvaluator resolves
 * variable references at evaluation time. For example, instances of this class
 * can implement their own variable lookup mechanisms, or introduce the notion
 * of "implicit variables" which override any other variables. An instance of
 * this class should be passed when evaluating an expression.
 * </p>
 * 
 * <p>
 * An instance of this class includes the context against which resolution will
 * happen
 * </p>
 * 
 * @since 2.0
 * @deprecated
 */
public interface VariableResolver {
	// -------------------------------------
	/**
	 * Resolves the specified variable. Returns null if the variable is not
	 * found.
	 * 
	 * @param pName
	 *            the name of the variable to resolve
	 * @return the result of the variable resolution
	 * 
	 * @throws ELException
	 *             if a failure occurred while trying to resolve the given
	 *             variable
	 */
	public Object resolveVariable(String pName) throws ELException;

	// -------------------------------------
}
